Blender to Unity. Particle Settings
1000 Stamen is quite a lot, are you sure you need that many in Unity to make it look good? 
There are some solutions:  
Ignore the 35MB, let Unity optimize it. That would be np if there are no other objects in the scene 
make sure the stems have as few vertices as possible and reduce their number. 
If the stem source object(s) have modifiers on them either remove or apply them, that way Blender should create instanced meshes, which Unity understands 
If you are fine with coding, export one stamen and replicate it in Unity. FBX is usually the best format to exchange 3D models, it can handle instances, carefully check the export settings (choose export and where you are supposed to state the file location, press n). You don't need any import settings to support instances, but also go through the options of the fbx import in Unity, there's often stuff you can customize to fit your specific situation.